DATAGIRD按钮列的问题

Question

我在DELETE按钮列编码如下
private void DataGrid1_DeleteCommand(object source, System.Web.UI.WebControls.DataGridCommandEventArgs e)
{
if(e.CommandName=="Delete")
{
dbutil dtl=new dbutil();
                this.DataGrid1.DataKeyField="itemid";
string itemid=this.DataGrid1.DataKeys[e.Item.ItemIndex].ToString();
this.Label1.Text=itemid;
SqlCommand cmd2=new SqlCommand();
cmd2.Connection=new SqlConnection(dtl.constr());
string sqlstr2="delete from lineitem where orderid="+Page.Session["orderid"]+" AND itemid="+itemid+"";
cmd2.CommandText=sqlstr2;
cmd2.CommandType=CommandType.Text;
cmd2.Connection.Open();
cmd2.ExecuteNonQuery();
cmd2.Connection.Close();
SqlCommand cmd4=new SqlCommand();
cmd4.Connection=new SqlConnection(dtl.constr());
string sqlstr4="select price,quantity,item.itemid from lineitem ,item where orderid="+Page.Session["orderid"]+"AND item.itemid=lineitem.itemid";
cmd4.CommandText=sqlstr4;
cmd4.CommandType=CommandType.Text;
SqlDataAdapter da4=new SqlDataAdapter(cmd4);
DataSet ds4=new DataSet();
da4.Fill(ds4);
this.DataGrid1.DataSource=ds4.Tables[0];
                
this.DataGrid1.DataBind();
}
运行时显示错误,是E.ITEM.ITEMIDEX超出了索引范围,请高手们帮忙回答一下

Answer 1

this.DataGrid1.CurrentPageIndex=0;用这一句把页面指向第一页

Answer 2

加了还是不行啊,在说我的只有一页啊提示是
索引超出范围。必须为非负值并小于集合大小。参数名: index 
里面就一句出错string itemid=this.DataGrid1.DataKeys[e.Item.ItemIndex].ToString();应该就这一句了吧,为什么e.Item.ItemIndex会不行呢